The proud eagle, noble symbol of freedom. But when you gotta go, you gotta go. Image courtesy of IStock.

In 1923, Southern California Edison had a problem. After having tapped into hydroelectric dams in the Sierra Nevada to serve their power-hungry Los Angeles customers with 220,000 volts, the company began receiving reports of short circuits and resulting power interruptions.

Finding the source of the issue would be no easy feat: The cables connecting the dams to the city stretched for 241 miles—at the time, the world’s longest—and the problem could be anywhere along the way.

Edison employees huddled for a solution, speculating on everything from lightning storms to spider webs holding moisture. Months passed with no plausible reason for the outages. A planned upgrade was in danger of being canceled. Big Creek, the site of the dams, had done everything it could to rearrange nature to suit its needs: forests were altered, clouds seeded. Everything seemed to be in order.

Eventually, an explanation was within sight: one worker noticed an eagle surveying the land from the top of a transmission tower. The majestic creature took off, soaring into the sky—and leaving a less-than-majestic trail of poop in its wake.

This bird had plenty of friends. It turned out that flocks of birds producing "voluminous streams of bird excrement" were to blame for the power outages.

Etienne Benson, P.h.D., a University of Pennsylvania professor, recently examined this fecal mystery in a paper [PDF] for the Environmental Humanities journal. Drawing upon the work of engineer Harold Michener and the power company's archives, Benson discovered accounts of the poo conducting electricity from the wires, overloading capacity, and creating flashovers, which diverted power to the steel towers and into the ground. The feces didn’t even need to touch the wires to pass along electricity. And because the energy essentially destroyed the droppings, the birds left no evidence of their dastardly doo doo. It was the perfect crime.

Once Edison determined the problem was excrement, they had to find a way to address it. Fortunately, among Edison’s employees tasked with a solution was the engineer Michener, who also happened to be an amateur ornithologist. The company first installed relays that took some of the load off areas that were used for avian toilet trips, then installed bird guards to prevent vulnerable areas.

The birds, however, would not be so easily dissuaded. They just moved to the next closest perch; because of wind, their poop had a reach farther than Edison had anticipated. Unable to deter the birds from landing, the company next installed excrement pans to catch the feces before it landed on the power line. When that didn’t prove entirely successful, three-inch iron “teeth” were placed on crossbeams, making landing a painful proposition for the birds.

The combination of poop-catch pans and unwelcoming spikes finally brought down the number of flashovers—and killed all the other competing theories for the cause of the problems. As Benson writes: “That is, it was not some mysterious and spectacular new electrical phenomena, as yet undiscovered by scientists, that was to blame for the flashovers, but rather something far more mundane: bird [poop].”

[h/t Science Daily]